Newly Identified CYP2C93 Is a Functional Enzyme in Rhesus Monkey, but Not in Cynomolgus Monkey

Cynomolgus monkey and rhesus monkey are used in drug metabolism studies due to their evolutionary closeness and physiological resemblance to human. In cynomolgus monkey, we previously identified cytochrome P450 (P450 or CYP) 2C76 that does not have a human ortholog and is partly responsible for species differences in drug metabolism between cynomolgus monkey and human. In this study, we report characterization of CYP2C93 cDNA newly identified in cynomolgus monkey and rhesus monkey. The CYP2C93 cDNA contained an open reading frame of 490 amino acids approximately 84–86% identical to human CYP2Cs. CYP2C93 was located in the genomic region, which corresponded to the intergenic region in the human genome, indicating that CYP2C93 does not correspond to any human genes. CYP2C93 mRNA was expressed predominantly in the liver among 10 tissues analyzed. The CYP2C93 proteins heterologously expressed in Escherichia coli metabolized human CYP2C substrates, diclofenac, flurbiprofen, paclitaxel, S-mephenytoin, and tolbutamide. In addition to a normal transcript (SV1), an aberrantly spliced transcript (SV2) lacking exon 2 was identified, which did not give rise to a functional protein due to frameshift and a premature termination codon. Mini gene assay revealed that the genetic variant IVS2-1G>T at the splice site of intron 1, at least partly, accounted for the exon-2 skipping; therefore, this genotype would influence CYP2C93-mediated drug metabolism. SV1 was expressed in 6 of 11 rhesus monkeys and 1 of 8 cynomolgus monkeys, but the SV1 in the cynomolgus monkey was nonfunctional due to a rare null genotype (c.102T>del). These results suggest that CYP2C93 can play roles as a drug-metabolizing enzyme in rhesus monkeys (not in cynomolgus monkeys), although its relative contribution to drug metabolism has yet to be validated

An Empirical Method for Estimating Normal Boiling Point and other Physical Properties of Alkene Hydrocarbons

金沢大学工学部A method of estimating the structural variation in the boiling point and other physical properties of alkenes is developed. By this method, all properties are expressed in terms of a structural constant called the “effective carbon number” which depends on the number and relative position of double bonds and those of side chains but not on external variables such as the temperature. An empirical equation is presented to correlate the effective carbon number with molecular structure. By combining the use with the previously presented nomogram, it is proved to be quite useful for rapid evaluation of various properties including the temperature-vapor pressure relationship and the critical constants

Bat Coronaviruses and Experimental Infection of Bats, the Philippines

Virus-infected fruit bats showed no signs of clinical infection

Structural basis for channel conduction in the pump-like channelrhodopsin ChRmine

新規光駆動型イオンチャネルの構造解明と高性能分子ツールの創出 --神経科学に光を当てる--. 京都大学プレスリリース. 2022-02-03.ChRmine, a recently discovered pump-like cation-conducting channelrhodopsin, exhibits puzzling properties (large photocurrents, red-shifted spectrum, and extreme light sensitivity) that have created new opportunities in optogenetics. ChRmine and its homologs function as ion channels but, by primary sequence, more closely resemble ion pump rhodopsins; mechanisms for passive channel conduction in this family have remained mysterious. Here, we present the 2.0 Å resolution cryo-EM structure of ChRmine, revealing architectural features atypical for channelrhodopsins: trimeric assembly, a short transmembrane-helix 3, a twisting extracellular-loop 1, large vestibules within the monomer, and an opening at the trimer interface. We applied this structure to design three proteins (rsChRmine and hsChRmine, conferring further red-shifted and high-speed properties, respectively, and frChRmine, combining faster and more red-shifted performance) suitable for fundamental neuroscience opportunities. These results illuminate the conduction and gating of pump-like channelrhodopsins and point the way toward further structure-guided creation of channelrhodopsins for applications across biology

C9orf72-derived arginine-rich poly-dipeptides impede phase modifiers

Nuclear import receptors (NIRs) not only transport RNA-binding proteins (RBPs) but also modify phase transitions of RBPs by recognizing nuclear localization signals (NLSs). Toxic arginine-rich poly-dipeptides from C9orf72 interact with NIRs and cause nucleocytoplasmic transport deficit. However, the molecular basis for the toxicity of arginine-rich poly-dipeptides toward NIRs function as phase modifiers of RBPs remains unidentified. Here we show that arginine-rich poly-dipeptides impede the ability of NIRs to modify phase transitions of RBPs. Isothermal titration calorimetry and size-exclusion chromatography revealed that proline:arginine (PR) poly-dipeptides tightly bind karyopherin-β2 (Kapβ2) at 1:1 ratio. The nuclear magnetic resonances of Kapβ2 perturbed by PR poly-dipeptides partially overlapped with those perturbed by the designed NLS peptide, suggesting that PR poly-dipeptides target the NLS binding site of Kapβ2. The findings offer mechanistic insights into how phase transitions of RBPs are disabled in C9orf72-related neurodegeneration

DNA Methylation Dynamics in Human Induced Pluripotent Stem Cells over Time

Epigenetic reprogramming is a critical event in the generation of induced pluripotent stem cells (iPSCs). Here, we determined the DNA methylation profiles of 22 human iPSC lines derived from five different cell types (human endometrium, placental artery endothelium, amnion, fetal lung fibroblast, and menstrual blood cell) and five human embryonic stem cell (ESC) lines, and we followed the aberrant methylation sites in iPSCs for up to 42 weeks. The iPSCs exhibited distinct epigenetic differences from ESCs, which were caused by aberrant methylation at early passages. Multiple appearances and then disappearances of random aberrant methylation were detected throughout iPSC reprogramming. Continuous passaging of the iPSCs diminished the differences between iPSCs and ESCs, implying that iPSCs lose the characteristics inherited from the parent cells and adapt to very closely resemble ESCs over time. Human iPSCs were gradually reprogrammed through the “convergence” of aberrant hyper-methylation events that continuously appeared in a de novo manner. This iPS reprogramming consisted of stochastic de novo methylation and selection/fixation of methylation in an environment suitable for ESCs. Taken together, random methylation and convergence are driving forces for long-term reprogramming of iPSCs to ESCs

Triglycerides and blood pressure in relation to circulating CD34-positive cell levels among community-dwelling elderly Japanese men: a cross-sectional study

Background: Triglycerides are reported to be positively associated with blood pressure (both systolic and diastolic). However, in a previous study, we reported a significant positive association between triglycerides and circulating CD34-positive cells (endothelial repair) among non-hypertensive, but not hypertensive, participants. Since hypertension and endothelial dysfunction have a bi-directional association (vicious cycle), the status of circulating CD34-positive cells may influence the association between triglycerides and hypertension. Methods: Since antihypertensive medication use may influence results of the present study, we conducted a cross-sectional study of 327 community dwelling elderly (aged 60-69 years) Japanese participants who were not taking anti-hypertensive medication and who had participated in a general health check-up in 2013-2015. Results: Participants were classified into two groups based on median values of circulating CD34-positive cells (0.93 cells/μL). For participants with lower circulating CD34-positive cells (n = 165), a significant positive association was seen between triglycerides and blood pressure, but not for participants with higher circulating CD34-positive cells (n = 162). The multivariable standardized parameter estimates (β) and p values of systolic blood pressure and diastolic blood pressure were 0.23 (p = 0.007) and 0.18 (p = 0.036) for participants with lower circulating CD34-positive cells and 0.08 (p = 0.409) and 0.03 (p = 0.786) for those with higher circulating CD34-positive cells. Conclusion: A significant positive association between triglycerides and blood pressure exists among those with lower, but not higher, circulating CD34-positive cells. The level of circulating CD34-positive cells acts as a determinant factor for the association between triglycerides and blood pressure

Impact of single nucleotide polymorphism on short stature and reduced tongue pressure among community-dwelling elderly Japanese participants: a cross-sectional study

Background: Asian-specific single nucleotide polymorphism (SNPs) (rs3782886) is reported to be associated with myocardial infarction; sarcopenia is reported to be associated with coronary subclinical atherosclerosis. On the other hand, short stature has been revealed as an independent risk factor for cardiovascular disease. However, no studies have reported on the association between sarcopenia and short stature nor on the impact of rs3782886 on this association. Methods: Since reduced maximum voluntary tongue pressure against the palate (MTP) reflects one aspect of sarcopenia, we conducted a cross-sectional study of 537 community-dwelling elderly Japanese participants aged 60?89 years who had participated in a general health checkup in 2015. Short stature was defined as values at or under the 25th percentile, and reduced MTP was defined as the lowest tertile of the study population (<158.0 cm and <26.5 kPa for men, <145.0 cm and <24.1 kPa for women). Results: Independent of classical cardiovascular risk factors, short stature was revealed to be positively associated with reduced MTP. The adjusted-odds ratio (OR) and 95% confidence interval (CI) of reduced MTP for short stature was 1.87 (1.19, 2.94). We also found that independent of known cardiovascular risk factors, with the non-minor homo of rs3782886 taken as the reference group, the adjusted OR and 95% CI for short stature and reduced MTP of the minor homo allele were 3.06 (1.23, 7.63) and 3.26 (1.33, 8.03), respectively. Conclusion: Short stature is independently associated with reduced MTP, with Asian-specific SNPs possibly playing an important role in this association

Effects of exercise training on gingival oxidative stress in obese rats

Objective: The purpose of the present study was to investigate the effects of exercise training on serum reactive oxygen species (ROS) level and gingival oxidative stress in obese rats fed a high-fat diet. Design: Rats were divided into three groups (n = 14/group): one control group (fed a regular diet) and two experimental groups (fed a high-fat diet with and without exercise training [treadmill: 5 days/week]). The rats were sacrificed at 4 or 8 weeks. The level of serum reactive oxidative metabolites (ROM) was measured as an indicator of circulating ROS. The level of 8-hydroxydeoxyguanosine (8-OHdG) and reduced-form glutathione (GSH)/oxidised-form glutathione (GSSG) ratio were determined to evaluate gingival oxidative stress. Results: The obese rats fed a high-fat diet without exercise training showed higher serum ROM levels [Carratelli Units (CARR U)] (mean +/- SD; 413 +/- 64) than the control (333 +/- 12) at 4 weeks (p = 0.023). Such a condition resulted in higher 8-OHdG levels (ng/mg mtDNA) (0.97 +/- 0.18) (p < 0.05) and a lower GSH/GSSG ratio (17.0 +/- 3.1) (p < 0.05) in gingival tissues, compared to the control (0.55 +/- 0.13 for 8-OHdG and 23.6 +/- 5.8 for GSH/GSSG ratio) at 8 weeks. In addition, the obese rats fed a high-fat diet with exercise training showed lower serum ROM (623 +/- 103) (p<0.001) and gingival 8-OHdG levels (0.69 +/- 0.17) (p = 0.012) than those without exercise training (1105 95 for ROM and 0.55 +/- 0.13 for 8-OHdG) at 8 weeks. Conclusions: Obesity prevention by exercise training may effectively suppress gingival oxidative stress by decreasing serum ROS in rats